To properly understand the post-harvest loss in grains, we need to know where and how it occurs. Therefore, in this article, we will answer the questions; 

1. “Where do post-harvest losses occur?
2. How do post-harvest losses in grains occur? 

What is a post-harvest loss in grains?

Post-harvest loss in grains is described as a reduction in the quality and quantity of grains. When this happens, it is because grains either went bad (grain spoilage) or were spilled along the value chain, from harvesting to consumption.

What is the value chain?

The value chain of food or grain production refers to the various stages through which food or grain is produced and delivered to the consumer. The stages include;

• Pre-drying: the process by which crops are dried whilst on the stalk of their plants on the farm before harvesting. 
• Plucking or Stripping: the process of manually removing the crops or grains from the plants. 
• Threshing or shelling: the process of removing grains from the cob or heads of the crop. Some common threshing practices include grinding on stones, beating with sticks on the ground or in a sack. 
• Winnowing: the process of removing impurities such as a leaf, stalk, empty seeds, and sand is removed from the grains.
• Bagging: the process of packing grains into bags or sacks for transporting from the farm or threshing site to the storage or warehouse.
• Transportation: the process of transporting bagged grains from one place to another
• Storage: the stage where grains are stored to be sold or consumed.

Post-harvest loss in grains along the value chain

Post-harvest losses in grains occur in many different ways depending on which stage of the value chain it’s happening at. For instance;

• Pre-drying: at pre-drying, post-harvest loss occurs when insects and birds attack the grains, eating from the stalk or infesting the grains with diseases.
• Plucking/stripping; this is how most grains are harvested and if done improperly, with the wrong tools grains are left damaged
• Threshing/shelling; some common practices include grinding grains on stone or beating a bag of grains against a stamp. This exertion of force if not done gently can leave the grains broken or cracked, which amounts to post-harvest loss
• Winnowing: during winnowing, good grains can be mistaken for impurities and thrown away.
• Bagging: if bagging is hastily done, plenty of grains will be lost to the ground while attempting to put them in a sack or bag. If airtight bags or sacs are not used, grains might be open to atmospheric moisture with can lead to mold growth
• Transportation: If bags aren’t well secured there is a high chance of bags falling off the trucks while being transported. Grains lost in the process will be counted as post-harvest loss.
• Storage: When crops are stored under unsuitable conditions such as in high humidity, it creates a favorable environment for grain spoiling bacteria to thrive. If the storage facility is unclean, rodents and pests will thrive and attack grains, causing post-harvest loss.

The takeaway

Post-harvest losses in grains occur along the value chain of grain production. This value chain includes harvesting, drying, winnowing, bagging, transportation, and storage. Post-harvest losses in grains occur when grains are not properly handled along the value chain, causing a reduction in quantity and quality. Knowing where and how post-harvest losses in grains occur can help you properly manage the situation. You must be employing good practices that reduce the loss of grains both in quantity and quality at every stage of the value chain. This is known as post-harvest loss management.